> -----Original Message----- > From: Joerg Roedel [mailto:jroe...@suse.de] > Sent: Wednesday, May 24, 2017 4:45 AM > To: Deucher, Alexander > Cc: 'David Woodhouse'; 'Joerg Roedel'; Bjorn Helgaas; linux- > p...@vger.kernel.org; linux-kernel@vger.kernel.org; Daniel Drake; Samuel > Sieb > Subject: Re: [PATCH v2] PCI: Add ATS-disable quirk for AMD Stoney GPUs > > Hi Alexander, > > On Tue, May 23, 2017 at 07:54:12PM +0000, Deucher, Alexander wrote: > > I finally got an answer from the hw team and we validated ATS on > > stoney as well so in theory this patch shouldn’t actually be needed. > > I think we may actually be papering over some other issue. The > > following patch seems to also fix this issue (and other issues): > > https://www.spinics.net/lists/stable/msg172631.html > > Yeah, but it still looks to me like that the hardware got into some > weird state with the storm of ATS invalidations sent to it. > > The Completion-Wait loop timeouts seen in the original bug report > indicate that the IOMMU is waiting for a response that never comes. And > this is probably the ATS flush completion response from the GPU, as > disabling ATS on the GPU makes the issue disappear.
FWIW, the GPU driver does not actually use ATS at the moment so I don't think we should see any ATS transactions. Alex
